1. Field of the Invention
This invention relates in general to charge coupled devices and in particular to a novel charge coupled device and information storage device for storing and sequentially transferring electronic signals in representative of information.
2. Description of the Prior Art
Charge coupled devices have been well known for storing and transferring charges in a storage medium by the use of appropriate potentials applied upon an insulating layer overlying one surface of a medium. For example, the article entitled "Charge Coupled Imaging: State of the Art" which appeared in Solid State Devices 1973, pages 83 through 107 disclose a number of charge coupled devices as well as charge coupled image sensors.
Prior art charge coupled devices have used a plurality of aligned gates overlying an insulating layer on a substrate and wherein three phase clock signals are respectively applied to the gates.
Other charge coupled devices have utilized semiconductors having a layer of insulating material, as for example, silicon dioxide which varies in thickness and upon which aligned pairs of gates are arranged so as to operate with two phase clock signals.
It has also been known to provide asymmetrical doping under the gates so as to obtain asymmetrical charge distribution in the device. However, the use of three phase clock pulses, varying thickness of the insulating layer under the gates and asymmetrical doping results in complicated and expensive devices and methods particularly for obtaining the varying thickness of the insulating layer and the asymmetrical doping are very difficult to perform.